Compressor air bleed closure



Jan. 4, 1955 P. P. NEwcoMB COMPRESSOR AIR BLEED cLosuRE Filed Feb. 6, 1951 AIR INLET I //////LA i A a /l/l/ll/lll//lllll/l/ll,

lill/1111111111 711 FICELE United States Patenti y UnitedA Afrcraft'Corporation, East Hartford, Conn., al

1r-f Delaware Application-February' 6, 19s1-,seria1- No. 209,682- 9elaims.- (olaz-satana) present invention` relates to multistage compressor-siv and particularly to an arrangement forbleeding and fl?! controllingthe bleeding provided at selected stages of the compressor.

En orderto: obtain best performance at design speed in; axial flow; compressors ithas been found necessary to prov-ide fofy bleeding the compressor at certain stages dur-ing the period while the compressor is brought up to. design speed. To accomplish this, a row of bleed holes is provided in the compressor casing' with the row extending generally almost the entire circumference of the casing in order that bleeding may be uniform at all points inthe c ir-curn'ference.4 A feature of thisl invention is an arrangementV for controlling the bleeding that occurs by opening or closing the ports; Another feature is an arrangement; by which. the Vport closing means may :be actuated lay-fluid` under pressure.

More specifically, the invention involves a flexible member surrounding the compressor casing and overlying the bleed? ports in sucha Way that when no pressure isAv applied thev ports are open and when pressure is applied the` member will closeof the'l fl'ow of gas through the Jr-ts. p Otherobjects and advantages. will be.- apparent from the:` specification and claims, and4 fromy the,y accompany-Dg drawings which illustrate an embodiment of the invention.

Fig. 1 is a fragmentary sectional view through a compressor.

Fig. 2 is a sectional view through the caslng substantially on line 2-2 of Fig. 1 on a smaller scale.

The invention is shown in connection with a multistage axial flow compressor in which the several rows of stator vanes 2 are carried by a casing 4, successive rows being spaced apart to alternate with the successive rows of blades 6 carried by the rotor 8. The inner ends of the stator vanes may carry shrouds 9 and sealing ns 10.

The invention is shown in a double walled casing which may be similar to that described and claimed in the copending Ledwith and Shoup application Serial No. 20?,- 556 filed February 6, 1951. As shown the inner casmg member 4a to which the stator vanes are directly secured has a row of ports 12 located directly downstream of one of the rows of stator vanes and also, in certain constructions, another row 14 of bleed ports located directly downstream of a succeeding row of stator vanes. This inner casing member 4a may have circumferentially arranged flanges 16 which extend outwardly into contact with the outer casing member 4b thereby defining annular chambers 18 and 20 communicating with the rows of bleed ports 12 and 14, respectively. The outer casing member 4b will have bleed ports 22 and 24 communicating with the annular spaces 18 and 20 and each of these rows of ports preferably extends circumferentially around the compressor. The flanges 16 prevent discharge of air out of chambers 18 and 20.

To control the flow of air out of the rows of ports 22 and 24 there is positioned in overlying relation to these rows of ports a flexible tube 26 located in an annular chamber defined by a box-like structure or casing ring 28 which extends around the compressor casing and may be held in position thereon as by welding 30. In the arrangement shown the box-like structure is made up of two separate rings, one of which is secured to the Acasing member 4b and the other of which surrounds the first ring and is secured at its edges to the first ring. The structure of this box is not critical but it will be noted 4 2,698,711 Patented Jan. 4, 1955 lsf:

. 2 l that-,it has outlet-ports 32 located in the side wall in suelr aA position that the tube' 26 when deflated into the dotdash line position showin will uncover the ports :l2 andalso the bleed ports; 22 and 24` and; will establish fluidn communication between them.

In theoperation ofthe device, when the-,compressor requires: bleeding,A the tube 26 is deflatedas, for example,-

through al two-way valve 34 which connects inletpassage 316L to a; vent 38. This allows tube 26 to collapse-,and air l0 withinthe compressor may then escape through the bleed .f p orts 22 and 24and through the outlet ports 32 into the atmosphere.; When the compressor reaches design-speed Or whenever bleeding is' not required air is admitted to the tube as through pressure conduit 40 and will inflate the. tube and move it into the full line position in which pit closes the ports 22, 24 and 32 and;- efectively prevents any further escapeofl air from within the; compressor.

The air conduit 40 may be connected to` any suitable source of supply of fluid underpressure with the admis,-

sion ofv fluid under pressure to the tube manually controlled as by a, valve. 34. Although the invention'is shownin a continuous complete tube it will be understood thatthe effective part of the tube is the movable portion. which constitutes a flexible memberr overlying the ports and movable by pressure exerted on the side remote from the ports into a position for closing' the ports.

It; is to be understood that the invention is not limit-ed to the specific embodiment herein illustrated and de-' scribed, but may be used in other ways` without departure; fromits spirit as defined by the. followingclaims.

lclaim: l-. A multistage.compressor-having a casing with, a row of-,portsqsurrounding the casing, each of said ports extending through the casing between successive: stages for bleeding the compresson and meansfor closing said port-s, f L 1, said mea-ns includ-ing a flexible; member surrounding the casing and overlying said ports and being normally in spaced relation thereto, said flexible memberV being movable intoj andout 0f, port closing position; and means having a connection with said member for applying pressure to the side of said member opposite to the ports for moving said member against said ports to prevent escape of fluid from within the casing.

2. A multistage compressor having a casing with a vrow of ports surrounding the casing, each of said ports extending through the casing between successive stages for bleeding the compressor, and means for closing said ports externally of the casing, said means including a flexible member surrounding the casing and overlying said ports and being normally in spaced relation thereto, said flexible member being movable into and out of port closing position, and means haivng a connection with said member for applying fluid pressure to the side of said member opposite to the ports for moving said member against said ports to prevent escape of fluid from within the casing.

3. A multistage compressor having a casing with a row of ports surrounding the casing, each of said ports extending through the casing between successive stages for bleeding the compressor, and means for closing said ports, said means including a flexible member surrounding the casing and overlying said ports and being normally in spaced relation thereto, said flexible member being movable into and out of port closing position, a

ring around said flexible member on the side of the flexible member opposite to the ports and supporting said flexible member, and means having a connection with said member for supplying fluid under pressure to the side of said member opposite to the ports for moving said member against the ports to prevent escape of fluid from Within the casing.

. 4. A compressor having a casing with bleed ports extending through said casing and arranged n a row circumferentially around its periphery, an inflatable tube overlying said ports, and means extending around the casing for supporting said tube such that when deflated, the tube will be spaced radially outwardly from and will uncover said ports, and means having a connection with said tube for inflating the tube into a position to close the ports. i

5. A compressor having a casing withbleed ports exwhen inated the tube will extend over and close said ports.

6. A compressor having a casing with bleed ports extending through said casing and arranged in a row circumferentially around its periphery, an inatable tube overlying said ports, and a ring extending around said compressor casing and defining a chamber enclosing said tube to position said tube in overlying relation to said ports, said chamber supporting said tube in such a manner that the tube, when deated, is in spaced relation to said ports for uncovering them, and means having a connection with said tube for inating said tube into a posi tion to close said ports.

7. A compressor having a casing with rows of stator vanes positioned therein, a rotor within said casing having rows of blades alternating with the rows of vanes, said casing having ports extending through the casing and located between successive rows of vanes, said ports being arranged in a row circumferentially of the casing, a ring surrounding said casing and forming a chamber overlying said row of ports, said ring also having ports therein for the escape of air from the chamber, a tiexible member in said chamber at one side of both sets of ports and normally spaced from said ports in the casing and ring to allow uid ow between the ports in the casing and the ports in the ring, and means having a connection with the ring for applying uid under pressure to the side of said exible member opposite to the ports for moving said exible member into a position to close both sets of ports by contact with the ring and casing adjacent to each of the ports.

8. A compressor having a casing with rows of stator vanes positioned therein, a rotor within said casing having rows of blades alternating with the rows of vanes, said casing having ports extending through the casing and located between successive rows of vanes, said ports being arranged in a row circumferentially of the casing, a ring surrounding said casing and forming a chamber overlying said row of ports, said ring also having ports thereln tor the escape of air from the chamber, and a flexible tube located in said chamber and supported by the ring in a position when deated to uncover the ports in the casing and ring and to allow for a ow of fluid between the casing ports and the ring ports, and means having a connection with said tube for supplying uid under pressure to the tube to expand it into port closing position.

9. A compressor having a casing with rows of stator vanes positioned therein, a rotor within said casing having rows of blades alternating with the rows of vanes, said casing having ports extending through the casing and located between successive rows of vanes, said ports being arranged in a row circumferentially of the casing, a ring surrounding said casing and forming a chamber overlying said row of ports,` said ring also having ports therein for the escape of air from the chamber, and a iiexible tube located in said chamber and supported by the ring in a position when deated to uncover the ports in the casing and ring and to allow for a ow of fluid between the casing ports and the ring ports, and means having a connection with said tube for supplying uid under pressure to the tube to expand it into port closing position, said ring being constructed and arranged to control the location of the tube such that it will close the ports when fluid under pressure is applied thereto.

References Cited in the tile of this patent UNITED STATES PATENTS 1,111,498 Rotter Sept. 22, 1914 2,492,149 Heuver Dec. 27, 1949 FOREIGN PATENTS 565,538 Great Britain Nov. 15, 1944 565,539 Great Britain Nov. 15, 1944 586,710 Great Britain Mar. 28, 1947 595,351 Great Britain Dec. 3, 1947 611,447 Great Britain Oct. 29, 1948 900,371 France Oct. 2, 1944 

